/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.formats.utils;

import org.apache.flink.api.common.serialization.DeserializationSchema;
import org.apache.flink.api.common.serialization.SerializationSchema;
import org.apache.flink.types.Row;

import org.hamcrest.Description;
import org.hamcrest.Matcher;
import org.hamcrest.TypeSafeMatcher;

import java.io.IOException;
import java.util.Objects;

import static org.apache.flink.util.InstantiationUtil.deserializeObject;
import static org.apache.flink.util.InstantiationUtil.serializeObject;

/**
 * Matcher that provides a common way for asserting results of {@link SerializationSchema}. It takes
 * into account e.g. the fact that serialization schema during runtime might be used after
 * serializing and deserializing it over a wire. Usage:
 *
 * <ul>
 *   <li>when asserting for result after serializing and deserializing a row
 *       <pre>{@code
 * final JsonRowSerializationSchema serializationSchema = new JsonRowSerializationSchema(rowSchema);
 * final JsonRowDeserializationSchema deserializationSchema = new JsonRowDeserializationSchema(rowSchema);
 *
 * assertThat(row, whenSerializedWith(serializationSchema)
 *     .andDeserializedWith(deserializationSchema)
 *     .matches(row));
 * }</pre>
 *   <li>to check if an exception is thrown during serialization:
 *       <pre>{@code
 * assertThat(row, whenSerializedWith(serializationSchema).failsWithException(instanceOf(RuntimeException.class)));
 * }</pre>
 * </ul>
 */
public abstract class SerializationSchemaMatcher extends TypeSafeMatcher<Row> {

    final SerializationSchema<Row> serializationSchema;

    private SerializationSchemaMatcher(SerializationSchema<Row> serializationSchema) {
        this.serializationSchema = serializationSchema;
    }

    public static SerializationSchemaMatcherBuilder whenSerializedWith(
            SerializationSchema<Row> serializationSchema) {
        return new SerializationSchemaMatcherBuilder(serializationSchema);
    }

    private static class SerializationSchemaResultMatcher extends SerializationSchemaMatcher {

        private final Row expected;
        private final DeserializationSchema<Row> deserializationSchema;

        private SerializationSchemaResultMatcher(
                SerializationSchema<Row> serializationSchema,
                DeserializationSchema<Row> deserializationSchema,
                Row expected) {
            super(serializationSchema);

            this.expected = expected;
            this.deserializationSchema = deserializationSchema;
        }

        @Override
        protected boolean matchesSafely(Row item) {
            try {
                return Objects.deepEquals(
                        deserializationSchema.deserialize(serializationSchema.serialize(item)),
                        expected);
            } catch (IOException e) {
                throw new AssertionError("Could not deserialize", e);
            }
        }

        @Override
        public void describeTo(Description description) {
            description.appendValue(expected);
        }
    }

    private static class SerializationSchemaExceptionMatcher extends SerializationSchemaMatcher {

        private final Matcher<? extends Throwable> exceptionMatcher;
        private Throwable thrownException = null;

        private SerializationSchemaExceptionMatcher(
                SerializationSchema<Row> serializationSchema,
                Matcher<? extends Throwable> exceptionMatcher) {
            super(serializationSchema);
            this.exceptionMatcher = exceptionMatcher;
        }

        @Override
        protected boolean matchesSafely(Row item) {
            try {
                serializationSchema.serialize(item);
            } catch (Exception e) {
                thrownException = e;
            }
            return exceptionMatcher.matches(thrownException);
        }

        @Override
        public void describeTo(Description description) {
            exceptionMatcher.describeTo(description);
        }

        @Override
        protected void describeMismatchSafely(Row item, Description mismatchDescription) {
            exceptionMatcher.describeMismatch(thrownException, mismatchDescription);
        }
    }

    /**
     * Builder for {@link SerializationSchemaMatcher} that can assert results after serialize and
     * deserialize.
     */
    public static class SerializationWithDeserializationSchemaMatcherBuilder {

        private SerializationSchema<Row> serializationSchema;
        private DeserializationSchema<Row> deserializationSchema;

        private SerializationWithDeserializationSchemaMatcherBuilder(
                SerializationSchema<Row> serializationSchema,
                DeserializationSchema<Row> deserializationSchema) {
            try {
                // we serialize and deserialize the schema to test runtime behavior
                // when the schema is shipped to the cluster
                this.serializationSchema =
                        deserializeObject(
                                serializeObject(serializationSchema),
                                this.getClass().getClassLoader());
                this.deserializationSchema =
                        deserializeObject(
                                serializeObject(deserializationSchema),
                                this.getClass().getClassLoader());
            } catch (IOException | ClassNotFoundException e) {
                throw new RuntimeException(e);
            }
        }

        public SerializationSchemaMatcher equalsTo(Row expected) {
            return new SerializationSchemaResultMatcher(
                    serializationSchema, deserializationSchema, expected);
        }
    }

    /** Builder for {@link SerializationSchemaMatcher}. */
    public static class SerializationSchemaMatcherBuilder {

        private SerializationSchema<Row> serializationSchema;

        private SerializationSchemaMatcherBuilder(SerializationSchema<Row> serializationSchema) {
            this.serializationSchema = serializationSchema;
        }

        public SerializationWithDeserializationSchemaMatcherBuilder andDeserializedWith(
                DeserializationSchema<Row> deserializationSchema) {
            return new SerializationWithDeserializationSchemaMatcherBuilder(
                    serializationSchema, deserializationSchema);
        }

        public SerializationSchemaMatcher failsWithException(
                Matcher<? extends Throwable> exceptionMatcher) {
            return new SerializationSchemaExceptionMatcher(serializationSchema, exceptionMatcher);
        }
    }
}
